Noises from the rear end

Hi!  I\'ve had an \'88 S12 for about a year now, and I\'m getting a couple of noises out the the rear end.  One is sort of a rumbling that I hear mostly at speeds under 5mph.  I think it could be the stub axle bearings, but I\'m not positive.  Any thoughts on this, or an easy way to find out?  The other noise is when I go over bumps, or accelerate hard; it feels like it could be worn bushings on the semi-trailing arms.  My repair manual has no information on how to replace them, or what parts to use, so any help there would be much appreciated.  Thanks!